Here are links to the real things mentioned in Seirial Experiments: Lain
Vannevar Bush's article in the Atlantic Monthly, "As We May Think"
Serial Experiments: Lain has several texts that are hard to read in it.
Some of them are from actual web pages.
Here are the links to the pages I could find.
This one is in the Accela Monologue
Appears in her monitor during Protocol when she is speaking as if she is reading her computer starting up
Communication with Alien Intellegence
Anything below this line is Tripod's doing.